<<"As we only have limited time (definitely coming back for longer next time!), can I ask if the Männlichen to Kleine Scheidegg, the Lauterbrunnen to Stechelberg and the Grütschalp - Mürren walks can be done in the one day? Or is that a little too optimistic? :-)">>
Yes. Start early. Drive to Lauterbrunnen. Add about an hour at each end to get to from Sigriswil.
It would be best to take them in this order:
Drive to Lauterbrunnen. Go to Wengen and take the cableway up to Männlichen. On the way up, on the cograil from Lauterbrunnen to Wengen, just before you enter Wengen station, look to the right. For just a few moments you see the view I posted above, but perhaps not as far into the valley, because it is rare to have such a clear day as I did when i took that picture.
In Wengen walk 5 minutes slightly uphill to the base station ( in German, die Talstation) of the cable way to Männlichen. Large car. Ride up to Männlichen (the Bergstation). Stop for a cup of coffee or to use the toilets at the restaurant. Walk to Kleine Scheidegg. The 1 1/2 hour walk (nicknamed the Grannies' Trail because it is so easy) will take 2 hours or so,because you will want to stop to look or take some pictures along the way. As you near Kleine Scheidegg there are some short stretches of moderately down hill trail where the gravel can slip out from under your feet. I find a hiking staff invaluable at that stage, and I like to wear boots for ankle support. Many people walk the trail in sneakers; you don't need boots or shoes with lugged soles, but you will appreciate them if you wear them.
PLEASE walk in the direction from Männlichen to Kleine Scheidegg. You will begin to appreciate the fascination that many have for the Eiger. I have attached an image with a blow up of a crop to show the size of the hikers vs. the size of the mountain.
At Kleine Scheidegg, take the train down to Lauterbrunnen.
Go across the street, ride the cable way up to Grütschalp.
Walk to Mürren. Modestly up hill, but you face the Jungfrau Massif. If you walk the other way - downhill from Mürren, you have to keep turning around to look back over your shoulder.
The train that parallels your walk stops at Winteregg if you want to shorten the trip.
After you arrive in Mürren, walk 5-10 minutes to the station for the cableway that goes up to Schilthorn, or down to Stechelberg, ride down to Stechelberg ( two stages, 30 second transfer at Gimmelwald in the same building) .
From Stechelberg, it is a 4+ km walk to Lauterbrunen along an easy, mostly level path or road. If you begin to run out of time, and are walking along the bus route, you can catch a bus to Lauterbrunnen.
I put that last so that you can grab a bus if you run short of time or energy.
This map can be made to show the bus stops. In the menu, under Points of Interest/Traffic turn on the various types of stations, etc. I have done so.
map.search.ch/Schratte nfluh?x=-1965m&y=-29239m&z=32&poi=bergba hn,haltestelle,parkhau s
Get your car and drive back to Sigriswil, wishing that you had decided to stay in Wengen. ;-)